If there is an exception that indicates that the shard isn't available then the exception should bubble up to the TransportShardSingleOperationAction class, so the shard level request can be retried on a different shard. (multi term vector api)
Don't wrap the exception in an ElasticSearchException when shard isn't available.
If there is an exception that indicates that the shard isn't available then the exception should bubble up to the TransportShardSingleOperationAction class, so the shard level request can be retried on a different shard. (multi get api)